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Jean Dodds Seminar, Part IV

The last topic of the day was hypothyroidism. About 70% of the thyroid gland has to be destroyed before classic hypothyroid symptoms present, so Dr. Dodds spent a lot of time going over the early signs of hypothyroid that aren't commonly recognized as such:

General symptoms: lethargy, mental dullness, exercise intolerance, neurologic signs, weight gain, cold intolerance, mood swings, hyperexcitability, stunted growth, and chronic infections.

Neuromuscular symptoms: weakness, stiffness, laryngeal paralysis (which results in a changed bark), facial paralysis, a "tragic" facial expression, knuckling or dragging feet, muscle wasting, megaesophagus, head tilt, and drooping eyelids.

Dermatological problems: dry scaly skin and dandruff (which can be treated by bathing the dog in Murphy's Oil Soap), coarse dull coat, bilaterally symmetrical hair loss, "rat tail", "puppy coat", hyperpigmentation, seborrhea or greasy skin, pyoderma or skin infections, myxedema (coarse, thickened skin), and chronic offensive skin odour (smells like rancid butter).

Reproductive disorders: (males) infertility, lack of libido, testicular atrophy, hypospermia/aspermia; (females) prolonged interestrus interval, no heat cycles, silent heats, false pregnacy beyond the maiden heat, and weak, dying, or stillborn pups.

Cardiac abnormalities: slow heart rate (check when the dog is at rest and look for changes over time), arrhythmia, and cardiomyopathy.

Gastrointestinal disorders (chronic, not occasional bouts): constipation, diarrhea, and vomiting.

Hematologic disorders: bleeding, bone marrow failure, and low red blood cell count, white blood cell count, and platelets.

Ocular symptoms: corneal lipid deposits, corneal ulceration, uveitis (inflammation of the middle layer of the eye), dry eye, and tear duct infections.

Other disorders: IgA deficiency, loss of smell, loss of taste, glycosuria (glucose in the urine), chronic active hepatitis, and other endocrinopathies (adrenal, pancreatic, and parathyroid).

I've seen various of these symptoms and disorders discussed on Toller-L and the Holistic Toller group. While just one isn't necessarily diagnostic of hypothyroidism, having an affected dog tested for hypothyroidism is probably a good idea.

Link to nutrition: there is too much iodine in many commerical foods, and iodine suppresses thyroid production. If you're supplementing your dog's diet with kelp, don't feed too much of it as kelp has lots of iodine.

The typical age of onset of hypothyroidism is 1.5 - 3 years, but it can happen any time after puberty. A complete thyroid panel should be done annually or every two years. Blood for testing should be drawn between heats and after false pregnancies, which means 12-16 weeks after the start of a heat.

Hemolife is the diagnostic arm of Hemopet and will be doing its own thyroid tests within the next month. A complete basic thyroid profile includes T4, T3, FT4, FT3, T4AA, and T3AA. FT4 and FT3 measure the amount of free, bioavailable T4 and T3, while T4AA and T3AA measure autoantibodies. Additional tests are available for TSH (thyroid stimulating hormone) and TgAA (thyroglobulin autoantibody). The OFA thyroid registry performs limited thyroid panels and will miss about 8% of positives. If you want to send blood in to Hemolife, you can find the instructions for how to do this under "Services" on their website: www.hemopet.org. Hemolife will provide you with a breed-specific, age-specific interpretation of the results.

When interpreting the results of thyroid tests, you have to know your dog. Puppies have higher thyroid levels than adults, while geriatric dogs have lower levels. Large and giant breeds have lower thryoid levels, and sighthounds have higher levels. Rabies vaccines can raise TgAA levels, so wait at least 60 days post-vaccination before testing.

Dogs with autoimmune thyroiditis should NOT be bred, regardless of their clinical status, because autoimmune thyroiditis is a heritable trait. Relatives of potential breeders should be screened annually from puberty. Dr. Dodds recommends that dogs not be bred until at least the age of three (later is better) to allow time for the condition, if it exists, to show up.

Hypothyroid dogs can be treated with thyroxine. The half-life of thyroxine in the body is 12-16 hours, so it's better to give the dog two doses per day instead of one. Two doses per day will provide more constant levels of thyroxine. Thyroxine binds to calcium and soy, so it's better to dose directly by mouth rather than putting the pill in food. Give doses one hour before or three hours after meals. "Pill pockets" (e.g., a bit of bread, a dunk of peanut butter) to encourage the dog to eat the pill are fine.

When testing dogs on thyroxine, draw blood 4 to 6 hours post-pill, and have the full profile done to make sure everything's as it should be. Readings should be high if the blood is taken 4 to 6 hours post-pill. Dogs should be dosed based on their optimum weight, not their overweight weight.

Dr. Dodds recommended the Whole Dog Journal as a valuable source of information on all kinds of things.

And finally, proof that I'm not just making all this up:

Dr. Jean Dodds Seminar Certificate


( 2 comments — Leave a comment )
Mar. 24th, 2010 10:47 am (UTC)
Thanks for your article about hypothyroidism. I own a Toller suffering from this disorder and find it hard to find good information about it, especially in Dutch :-)
The diagnose was based on a TSH and T4 test. Is it still usefull to perform a TgAA test?
She was diagnosed at the age of 2, she turns 3 next May.
Mar. 25th, 2010 07:20 pm (UTC)
Re: hypothyroidism.
You're welcome--I'm glad someone found it useful!

It was my understanding that "regular" thyroid tests risked not diagnosing some (about 8%) dogs with the disease. If your dog has already been diagnosed, then I'm guessing that the TgAA test is not necessary. However, I am not an expert on this! The person to ask, of course, is Jean Dodds herself. You can contact her through the Hemopet website: http://www.hemopet.org/ .

I hope your girl is doing well.
( 2 comments — Leave a comment )